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xiii                         CHARACTERS OF  ARCTOIDEA                       425

swollen, and there is but little flattening towards the nieafcus :
the paroccipital processes, though slight, are in contact with the
bullae basally, though their free tips are turned away from them.
Finally, in Ictonyx the bullae are much swollen ; there is but little
flattening towards the meatus, and the paroccipital processes, them-
selves much swollen, are pressed closely against the bullae. The
Mustelidae, therefore, in this as in other characters^ approach the
Aehiroids.

There is no caecum, a feature which marks off the Arctoidea
from ail Carnivora except the "Viveirids Arandinia and A.-rctictis
(occasionally). The brain is characterised by the possession of

FIG. 2152.—Section of the left auditory foulla aud surrounding "bones of a Bear (27rsus
/erox). am, External auditory meatus ; MO, basioccipital; Cow, carotid canal ;
e, Eustachian canal ; g, glenoid canal; Sq, sqtiamosal; T, tympanic ; tt tympanic
ring. (From Flower, Proc. ZooL Soc. 1869.)
what Dr. Mivart has described as the " ursine lozenge," a tract
about the middle of the hemispheres, defined posteriorly by the
crucial sulcus, and formed by the emergence on to the surface of
the brain, of the Mppocampal gyrus.
The Arctoidea are very widely distributed. But there are
some curious exceptions. Thus there are no representatives of
the group (as might be expected) in the Australian region; they
are completely absent from Madagascar; while the true Bears
(family IJrsidae) are totally absent from Ethiopian Africa, and
are only represented by a single species, Ursus ornatus, In the
Neotropical region.
It   is   noteworthy  that   the Arctoidea   never   show  spots  or